This invention relates to the handling of bulk particulate solids and more particularly to a system for pneumatically conveying such materials in a simple, efficient and economical manner.
In the chemical processing and other industries, pneumatic conveying systems commonly are used to transport bulk particulate materials of various properties. The parameters of such systems generally are pressure drop, gas flow rate and conveying rate. Whether such systems are dilute phase or dense phase systems, they tend to incur a great many problems which impair their performance including less than desirable conveying rate, repeated line plugging, product degradation, excessive wear and vibration. Such problems further are exacerbated not only because of the construction or operation of the systems but because of the nature of the material being conveyed including its moisture, temperature and particle size. Accordingly, it is the principal object of the present invention to provide an improved system for pneumatically conveying dry, fine particle size material, at low velocity, in the dense phase, effectively and efficiently without undue wear on the system, degradation of product or excessive use of energy.
The aforementioned problems of prior art pneumatic conveying systems are largely overcome by the present invention in providing a system generally consisting of a material transporting line including a first conduit formed of a gas permeable material, providing a material flow passageway having an inlet and an outlet, a second conduit formed of a gas impermeable material, encompassing and spaced from the first conduit and a plurality of partition walls disposed between the conduits and spaced along the lengths thereof, defining a plurality of plenums; a nozzle connectable to a source of gas under pressure, projecting into such passageway for injecting a gas under pressure therein to impel material disposed in the passageway toward the outlet thereof; a gas supply line connectable to a source of gas under pressure, having branch lines each communicating with a plenum; and each of the branch lines having a pressure regulating means. The pressure regulating means provided in such branch lines supplying gas under pressure to the plenums may consist of different sized orifices or pressure regulating valves which may be designed to vary the pressures in the plenums along the length of the transport line. Material to be conveyed through the passageway of the transport line may be gravity fed or force-fed under pressure from a vessel, hopper, another transport line or any other means. In addition, multiple discharge segments provided with outlets of different cross sectional configurations may be provided which may be selectively, detachably mounted on the main body of the transport line.